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Bike component fitment: bottom bracket, headset, seatpost, axle

A Juliana Maverick uses a 30.9 mm class seatpost interface. The dimensions, how to confirm it on your frame, and how it compares to the neighbouring standards.

Updated 05 September 2026.

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What seatpost diameter does a Juliana Maverick use?

The seatpost fitment standard on a Juliana Maverick, and how to pick the right part.

DROPS IN
A Juliana Maverick uses a 30.9 mm class seatpost interface.
This frame's fitment
FrameJuliana Maverick
Seatpost diameter30.9 mm
Diameter30.9 mm
Typical classmany mountain bikes and full-suspension frames, and one of the two common dropper-post diameters

The Juliana Maverick uses a ZS44 zero-stack upper headset (zero stack, 44 mm), a 30.9 mm class seatpost, a 15x110 mm Boost front thru-axle at the front (15 mm x 110 mm Boost, front) and a braze-on front derailleur.

Most builds are 1x, so the front-derailleur mount note applies only to 2x setups. The rear is typically Boost 12x148; confirm your generation. The bottom bracket is covered on its own page.

The part to buy
Shop 30.9 mm seatpost for your Juliana Maverick on AmazonaffiliateFind 30.9 mm seatpost for your Juliana Maverick on eBayaffiliate
Related fitment pages
30.9 mm seatpost30.9 mmBottom bracket for Juliana Mavericksame frame, BB shellHeadset on a Juliana Mavericksame frame30.9 mm seatpost on a Giant Trance MTBsame standard, another frame

SOURCES: BikeGremlin, Seatpost diameter sizes (standards) · BikeRadar, Bike seatposts explained: diameters, materials, lengths · Park Tool, Standardized Headset Identification System (SHIS) · BikeRadar, Mountain bike axle standards: the complete guide

Questions and answers

What seatpost diameter does a Juliana Maverick use?

A Juliana Maverick uses a 30.9 mm class seatpost interface.